Java Area.intersects（Rectangle）超出范围

Question

im pretty new to programming so this might be really obvious, but when i run this part of my code

public void movePlayer(){
    Rectangle playerRect = new Rectangle((int) player.getxPositie(),(int) player.getyPositie()-12,20,35);

    if(water.intersects(playerRect)){//out of bounds????
        player.swim=true;
        jump=true;
        if(SplashP == true){
                SplashP=false;
                Splash((int) (player.getxPositie()/5),versnelling*12);
        }else{}

    }else{  player.swim=false;
            SplashP = true;}
        }
...

i get the following Exception and i don't know why

Exception in thread "Thread-20" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 0
    at java.util.Vector.get(Vector.java:748)
    at java.awt.geom.Area.getCachedBounds(Area.java:434)
    at java.awt.geom.Area.intersects(Area.java:606)
    at java.awt.geom.Area.intersects(Area.java:618)
    at Model.movePlayer(Model.java:723)
    at Animator.run(Animator.java:19)
    at java.lang.Thread.run(Thread.java:745)

Another strange thing is that when the water intersects the player the else case alse gets triggerd half of the time

PS. Area water is build from a collection of triangles

Answer 1

I think that this intersects function does not allow for Rect input. I also advice you to make sure your code is in one language. I happen to know what your variables do because I am Dutch myself, but for the sake of consistency as well as everyone being able to read your code I advice you to make everything in English.

Answer 2

If you take a look at java.awt.geom.Area.getCachedBounds line 433-434 (see your stacktrace) then you find

private Rectangle2D getCachedBounds() {
    ...
    if (curves.size() > 0) {                 // 433
        Curve c = (Curve) curves.get(0);     // 434

curves is a member of Area of type Vector . The code checks if curves is not empty and then accesses the first element. This then raises an ArrayIndexOutOfBoundsException which can only happen when curves is empty.

So there must be another thread which modifies the water object in between.